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Finding the Fourth Proportional to 109.20, 163.44 and 78.84

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Solution

The fourth proportional to 109.20, 163.44 and 78.84 is: 118.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.20 : 163.44 = 78.84 : x
  2. Step 2: Convert to fraction form
    109.20/163.44 = 78.84/x
  3. Step 3: Cross multiply
    109.20x = 163.44 × 78.84
  4. Step 4: Simplify right side
    109.20x = 12,885.61
  5. Step 5: Solve for x
    x = 12,885.61/109.20
  6. Step 6: Final answer
    x = 118.00

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.